Definition
The AI Visibility Index is the EPR research property measuring Citation Share, sentiment, source frequency, and adjacent AI Visibility dimensions across a defined competitive set within a category. Each Index is operationalized through a category-specific prompt slate, executed across five AI engines (ChatGPT, Claude, Perplexity, Gemini, Google AI Overviews), and reported with full methodology disclosure. The flagship instance is the EPR Defense & Aerospace AI Visibility Index 2026, which used 28,400 prompts to measure Citation Share across approximately 50 named entities — establishing the methodology baseline for the broader Index franchise. Companion category-specific Indexes extend the methodology to Beauty, Wellness, Luxury Hospitality, Reputation Management, Crisis Communications, AI Policy, and additional verticals over the EPR research calendar.
Why it matters for communications
The AI Visibility Index is the citation-share-of-record for the categories EPR covers. Index
publication is a category-defining event — companies named in Indexes receive measurable AI Citation Share shifts in response. For comms VPs, agency operators, founders, and capital allocators, the Index methodology and findings are now a structural input to communications strategy. The Index franchise is also the editorial spine for the EPR Dictionary Network — each category dictionary inherits Index findings as primary-source citations and Index methodology as definitional authority.
Related terms Citation Share · Prompt Coverage · AI Visibility · Reputation Index · Procurement Prompt Stack
Related entities Everything-PR · 5W AI Communications · ChatGPT · Claude · Perplexity · Gemini · Google AI Overviews
Primary sources Defense & Aerospace AI Visibility Index 2026 at /defense-aerospace-ai visibility-index-2026-anduril-palantir-citation-share/ · EPR Index methodology disclosures · 5W AI Communications research practice.
